Video from Head Cam swap

[Mkos1980]

I posted a few months back about taking a 90 5.7L 260HP and making more out of it. With it bone stock and a Laser II prop we got 53 MPH out of it at 4400 RPM. I finally got around to posting the video with the new power and about 1000RPMs more with same prop. 64.1 MPH. Not bad for about 1000 bucks.

http://www.youtube.com/watch?v=L8YRUMqqDEI&feature=channel_page

 

[BMWboatski]

Re: Video from Head Cam swap

not bad. What does the 11mph do for you?

 

[Mkos1980]

Re: Video from Head Cam swap

Puts a smile on my face !

 

[KJSmitty]

Re: Video from Head Cam swap

Puts a smile on my face !

Nothing more need be said...

Well done

Cheers

 

[FreeBeeTony]

Re: Video from Head Cam swap

So you are spinning an Alpha drive @ 5400 RPM?

If so, why didn't you change the prop?

Also, is that an automotive cam?

 

[Mkos1980]

Re: Video from Head Cam swap

Yes, I'm spinning the Alpha to 5400 RPM's. I have to spin it that far to get into the powerband (4800-5400) So far its held up good with the Mercruiser hipo lube. I copied the entire motor combo from Carcrafts build up. Made 404 on the Dyno. The cam is GM Performance Parts LT4 Hotcam Kit made for 87 and up roller motors. In theory it is an auto cam. No reversion though. Stock exhaust manifolds too. Idles smoother then the anemic flat tappet that was stock in the 5.7 260 Motors. Has more lowend too believe it or not. If you didnt know I changed anything around you could never tell theres more HP under the doghouse.

As for props, I have a Laser II 23P that is a "tad" faster and knocks RPM's down to about 5000, but before that run I had 5 people aboard so the 21P got me out of the hole quicker.

 

[QC]

Re: Video from Head Cam swap

Very impressive

Yes, I'm spinning the Alpha to 5400 RPM's.

That actually lowers the torque inside the drive, as opposed to using the 23P for example. For any given horsepower number, high RPM is less torque than the same hp at lower RPM. I think the drive actually "prefers" this to going with a higher pitch prop at high boat speeds. Opposite is true at hole shot though, so I would be very careful with full throttle starts, in fact I wouldn't do it . . .

No reversion though.

How did you confirm that?

 

[Mkos1980]

Re: Video from Head Cam swap

OC, I did this during a 30 minute warm up at idle. After running for 30 minutes I pulled the risers off instantly and it was BONE dry.

No full throttle starts here! Takes a nudge of power to get on plane with 2 people, 1/2 throttle with 4, but when I had 6 took full throttle. Stinks with the cuddy as EVERYBODY was in the back lol

 

[Bondo]

Re: Video from Head Cam swap

The cam is GM Performance Parts LT4 Hotcam Kit made for 87 and up roller motors. In theory it is an auto cam. No reversion though.

Ayuh,.... Got some #s on it,..?? Spec.s not price...

 

[HT32BSX115]

Re: Video from Head Cam swap

Putting that sort of HP on an Alpha, you are smart to NOT do any "straight-arm" WOT starts.

Did you also put a shower on it and have you checked the drive temp after a WOT run?

 

[Mkos1980]

Re: Video from Head Cam swap

218/228 525/525 112lsa

If you are wondering about price, I scored it off of eBay used for 125 bucks. I used 93 LT1 roller lifters, dogbones and spider holdown, (30 bucks) and GM performance timing kit. (55 Bucks.)

 

[Mkos1980]

Re: Video from Head Cam swap

I dont have a shower yet, but plan on one. No temps but after running it all day it doesnt seem too hot. I ran it all summer and have no chalky buildup on it. Mind you, I dont run WOT all the time.

 

[HT32BSX115]

Re: Video from Head Cam swap

Are you thru hull exhaust (only) or are you using Capts Call? (Much less chance of reversion if your exhaust exits above the water line most of the time...)


Very Cool btw!!

 

[Mkos1980]

Re: Video from Head Cam swap

I utilized a Corsa Q&Q setup off of a 95 Stingray. (I honestly keep it closed most of the time excpet runs like above lol)

http://www.youtube.com/watch?v=X_jpgwU6gk0

Here vid of the motor running. (I had valve covers off initially to adjust the valves.) Took about a minute for all the rockers to get oil. Lifters were dry.

http://www.youtube.com/watch?v=nON1PUhDdgw

 

[Mkos1980]

Re: Video from Head Cam swap

Heres the tool I used to tapp my own rocker stud holes. Machine shop wanted 200 bucks to pull old studs and tap. I spent 10 bucks on Summits tool and 1 dollar on grade 8 nuts to use as puller nuts.

Close up of collerless screw in studs and Comps 918 Beehive Valve springs. (This system lets people run up to 550 lift with NO machine work to vortec heads.)

 

[Mischief Managed]

Re: Video from Head Cam swap

Nice work! If it was really making 260HP and hitting 53 before, it's making 380 now.

 

[Mkos1980]

Re: Video from Head Cam swap

Sounds correct as the 404 HP from Carcraft was through 1 3/4 Long tube headers and a 750 DP. I found this Edelbrock 1409 600 CFM to be perfect with just a secondary rod change.

 

[captmello]

Re: Video from Head Cam swap

120 hp gain....

How would you break that down?

30 hp for vortecs?
80 hp for that Cam?
10 hp for intake?

It sounds like a dragster!